Looking for offroad trails in France (close to German border)

[schattat]

Hey guys,

A buddy of mine and I plan on doing a day trip to France tomorrow (Sunday) and are looking for some advice on where to find some decent offroad track (legal ones! ) that aren't too far away from the border. We'll be coming from the Frankfurt area and trailering the bikes so we don't want to be driving for too long!

Any ideas would greatly be appreciated